Just how big can a snowflake get? It depends on what you mean by 'snowflake'

This 10.0 mm (0.4 inches) monster snowflake holds the Guinness record for the largest snow crystal. A microscope was used to photograph it in four quadrants, which were later digitally recombined. (Kenneth Libbrecht)

Here's a question to ponder during these cold, wintry days: How big can snowflakes get?

Part of the answer depends on what you mean by the word "snowflake." The other part of that answer depends on who you ask.